I want to simulate a gas burner which consists of venturi and burner. Fuel and 50% of air enter the venturi and goes to burner ports. In reality, combustion is ignited by a spark near the burner ports (outer side of the burner).

I setup two domains: inner burner and outer burner. inner burner is where the mixing happens and should be a cold flow without combustion. Inner burner and outer burner domains are connected with GGI fluid-fluid interface at ports.

The problem is that CFX only allow one same combustion model in these two domains. I can't even specify different parameter values for these two domains. So combustion occurs in the inner burner domain, which is not correct.

What I want to model is fuel and air first mix in the venturi and then combust at burner ports. However, with EDM combustion model, the mixture combusts right after they enter the venturi. So I want to specify two different values of combustion model parameters like extinction temperature for two domains so that combustion is not allowed in the venturi(extinction temperature=5000K), but allowed in the outer domain(300K).